Automotive pulleys are conventionally made by spinning sheet metal using a number of different processes known in the industry. However, for crankshaft dampers, in many cases the mass of the crankshaft damper pulley must be greater than that provided by ordinary sheet metal pulleys. Greater mass is required to give the required amount of inertia to damp crankshaft vibrations.
Conventionally, greater mass is achieved by using a cast iron pulley instead of a spun sheet metal pulley. The problem with cast iron is that due to its manufacturing process, i.e., casting in sand, it has to be machined to achieve the desired net shape. Machining is an expensive operation. In addition, machined grooves for a multi-ribbed pulley have a higher surface roughness than a spun part due to the existence of machining marks, namely, grooves. Furthermore, machining exposes porosities which are inherent in the iron casting. The sharp edges of the exposed porosities are detrimental to a belt running in the pulley grooves.
Machining the pulley grooves also cuts through the grains, creating a weaker structure than spinning or flow forming which flows the grain structure and also reduces the grain size and crystalline dislocation, creating a much stronger part. This is also referred to as work hardening.
Further, flow formed sheet metal parts can only be made to a certain thickness both economically and practically. This limit is up to about 5 mm of sheet metal thickness.
Methods are known for utilizing scrap in the recycling of materials to their raw state, but not to manufacture durable, functional, and net-shaped products.
Representative of the art is U.S. Pat. No. 4,585,475 to Fosnacht (1986) which discloses a method for recycling oily mill scale.
What is needed is a method of forming a metal matrix component and product using scrap metal material that is compacted and bound together by an adhesive. The present invention meets this need.